I haven't worked at Bluesky for over a year now. I'm genuinely excited about the protocol, and have written a bunch of things about it while I had free time between jobs. (Ironically I had no time to write about it while at Bluesky because I was too busy working around React Native bugs.)
>it's impossible to actually participate in Bluesky using an alternative relay
I don't know what you mean by this. https://blacksky.community/ is definitely running their own relay. Here's a community listing of some relays: https://atproto.at/relays.
Here's an example of connecting to one of them: https://pdsls.dev/firehose?instance=wss%3A%2F%2Feurope.fireh.... From an app's perspective, they're completely interchangeable, so as an app developer you can switch to any relay you want, or run your own.
Many apps don't even use a relay at all, instead relying on caches like https://constellation.microcosm.blue/.